Mushroomed shaped aluminum code cap top piece designed as an exhaust vent for kitchen, bath, laundry, water heater pipes that terminate through the roof. The unique design allows for sufficient airflow while protecting the inside of the structure from wind driven rain. Used heavily in the northern California market in lieu of t-top roof jacks. For 0.025 roof assembly. Top piece has three slots that the base tabs fit into to secure. Gibraltar Building Products 1/2-in to 4-in x 6-in Aluminum Vent